Needle clamp



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' NEEDLE CLAMP Filed Aug. 5. 1954 mum/r04 Hermann ZINE,

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United States. Patent" NEEDLE CLAMP Hermann Zink, Kaiserslautern, Germany, assignor to G. M. Pfaii A.-G., Kaiserslautern, Pfalz, Germany, a corporation of Germany Application August 5, 1954, Serial No. 447,973

Claims priority, application Germany August 17, 1953 8 Claims. (Cl. 112-226) The invention relates to needle clamps, and relates more particularly to needle clamps of the type that may removably be connected to the lower end of a needle bar of a sewing machine.

The invention will be explained in connection with the clamping of flat-faced shanks of sewing machine needles, but it will be understood that no limitation is intended thereby save as pointed out in the claims hereof.

It is among the principal objects of the invention to provide a needle clamp for clamping one or more sewing machine needles, for instance of the flat-faced shank type, for single or plural (for instance of the Bonnaz type) stitch operations, in which the interchange of needles is simple, and which may readily be switched between single, double, or triple stitching.

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the ac companying drawings, wherein:

Fig. 1 is a fragmentary frontal perspective view, partly in section, of a needle clamp in accordance with the invention;

Fig. 2 is a fragmentary rear perspective view, partly in section, thereof;

Fig. 3 is a large scale sectional view taken on line 3--3 of Fig. 1 disclosing a wedge for single needle clamping in accordance with one embodiment of the invention;

Fig. 4 is a frontal perspective view of the wedge shown in Fig. 3;

Fig. 5 is a large scale sectional view similar to Fig. 3, but embodying a modification including a wedge for two needles;

Fig. 6 is a rear perspective view of the wedge shown in in Fig. 5;

Fig. 7 is a large scale sectional view similar to Figs. 3 and 5, but embodying a further modification including a wedge for triple needles; and

Fig. 8 is a frontal perspective view of the wedge shown in Fig. 7.

In carrying the invention into effect in the embodiments which have been selected for illustration in the accompanying drawings and for description in this specification, and referring now particularly to Figs. l-4, there is provided a hollow body 3 that is removably connected to the lower end of the needle bar 1 of a sewing machine (not shown). The body 3 defines on the interior a cylindrical chamber 3a. The axis X-X of the cylindrical chamber 3a is at right angle to the direction A of reciprocal movement of the needle 25. A threaded passage 3b is provided in the body 3 at right angle to the axis X-X, and the passage 3b intercommnnicates with the interior of the chamber 3a and the exterior of the body 3. A screw 2 serves to connect the body 3 to the needle bar 1.

A set screw 6 is threaded in the passage 3b and includes a cam 7 of conical form that protrudes into the chamber 2 3a. The cone of the cam 7 is slender and the taper thereof i smaller.

In the embodiment shown in Figs. 3 and 4, there is disposed in the chamber 3a a wedge member 8 that has an annular front surface 15a from which there is recessed a conical surface 15. The annular surface 15a engages in abutment the fiat face 31 of the shank of the single needle 25. The needle 25 is placed centrally in intersection with the axis X-X, and the axis of the wedge 8 coincides with the axis X-X of the chamber 3a. A rear flange 11 and a front flange 12 are provided on the wedge 8 and engage the cylindrical surface of the chamber 3a.

Oppositely of the front face 15a, the wedge 8 has a conical cam face or cam surface 14, the taper of which is larger than the taper of the cam 7. The cam 7, as shown in Fig. 3, engages the cam face 14 along a single osculating point. By adjusting the position of the set screw 6, that osculating point will be closer to or further away from the axis X-X, and the cam 7' will adjustably exert pressure to press the wedge 8 against the surface 31 of the shank of the needle 25.

The wall of the body 3 is provided with a recess to reoeive the shank of the needle 25, and the recess has a depth which is smaller than the width of that shank so that, as shown in Fig. 3, the shank of the needle 25 will project for a portion into the chamber 311. Thereby, the abutment between the surface 15a of the wedge 8 and the surface 31 of the needle shank will be entirely in the chamber 3a, and the needle 25 thus be clamped.

The surface 31 of the needle shank will be engaged by two diametrically opposite points of the annular surface 15a of the wedge 8.

A modified arrangement for clamping the shanks of two needles 26 and 27 is shown in Figs. 5 and. 6. A wedge 9 is provided which engages the front surfaces of the shanks of both the needles 26 and 27. The front surface of the wedge 9 is again conically recessed at 18 and oppositely thereto there is provided a tapered cam face 17 that cooperates with the cam 7. The taper of the cam face 17 is again larger than the taper of the cam 7.

In the modification shown in Figs. 7 and 8, provision is made to engage simultaneously the shanks of three needles 28, 29 and 30. A wedge 10 is provided that has tapered surfaces 20 that are formed in a body 19, opposite a front surface 21. The taper of the cam-faces 20 is again larger than the taper of the cam 7 that engages the cam-faces 20.

On the front surface 21 there are provided three abutment bosses 22, 23 and 24 for engagement with the fiat surfaces of the shanks 30, 29 and 28, respectively.

In Fig. 3 there was shown a single recess for the shank of a single needle, while in Fig. 5 there are shown two recesses for two needles 26 and 27, and in Fig. 7 there are shown three recesses for the needles 28, 29 and 30. Each of these recesses has a smaller depth than the width of the needle shanks, so that each of the needle shanks projects for a portion into the chamber So for engagement by the respective wedge.

As the hollow body of Fig. 7 includes three recesses, namely the single recess of Fig. 3 and the double recesses of Fig. 5 that are spaced apart, the body of Fig. 7 may be used for either a single needle in the central recess, or for two needles in the two outer recesses, or for all three needles (Fig. 7), while using different wedges 8, 9 and 10, respectively.

It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific exemplifications thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appendedclaims .they shall not be limited to the specific exemplifications of the invention described herein.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows:

i. In a needle clamp, in combination, a hollow body elongated in the direction of the :needlemovement and defining on its interior a longitudinal chamber having its axis at a first angle to the direction of needle movement and forming a passage intercommunicating with said chamber and disposed at a second angle to said axis, said chamber being arranged for needle portion reception for needle clamping, a clamping wedge disposed in said chamber and beingslidable axially of said chamber and having a face for .needle portion engagement, and means adjustably disposed in said passage and being movable in said passage at said second angle to said axis, and operable from the exterior to engage said wedge for pressing it adjustably in direction axially of said chamber towards said needle portions, said means including a cam surface formed on said wedge oppositely of said face, and a set screw threaded in said passage and including a cam extending at an acute angle to the cam surface and projecting to the interior of said chamber and engaging said cam surface.

2. In a needle clamp as claimed in claim 1, said cam surface and cam being conical, the taper of said cam being smaller than the taper of said cam surface.

3. In a needle clamp as claimed in claim 2, said taper of said cam surface being axially of said chamber axis, and said taper of said cam being axially of the axis of said passage.

4. In a clamp for sewing machine needles having a hollow body including means for receiving and backing a needle shank, a cylindrical wedge member having a cylinder axis and being slidable on the interior of said body and having a surface engaging said shank to press it against said backing, said surface extending in the direction of needle sewing movement, and a set screw movable at right angle to the axis of said cylinder and operable for adjustably pressing said wedge member towards said shank, said set screw having a conical end surface,

and said wedge member having oppositely relative to said engaging surface a tapered surface, the angle between said conical surface and said axis being smaller than that between said tapered surface and said axis, said conical surface engaging said tapered surface.

5. in a clamp for sewing machine needles having a hollow body including means for receiving and backing a needle shank, a cylindrical wedge member having a cylinder axis and being slidable on the interior of said body and having a surface engaging said shank to press it against said backing, said surface extending in the direction of needle sewing movement, and a set screw movable at right angle to the axis of said cylinder and operable "for adjustably pressing said wedge member towards said shank, said wedge member having intermediate its ends an annular groove, a portion of the wall of said groove oppositely relative to said engaging surface being tapered, said set screw having a conical end surface engaging said tapered surface, said engaging surface having a conical depression, the axis of which coincides with the axis of said cylinder.

6. In a clamp for sewing machine needles having a hollow body including means for receiving and backing a needle shank, a cylindrical wedge member having a cylinder axis and being slidable on the interior of said body and having a surface engaging said shank to press it against said backing, said surface extending in the direction of needle sewing'movement, and a set screw movable at right angle to the axis of said cylinder and operable for adjustably pressing said Wedge member towards said shank, said wedge member having opposite said engaging surface a diametrical slot, the end surface of said slot being tapered flaring outwardly towards said engaging surface symmetrically of saidaxis, said set screw having a conical end surface engaging said tapered surface.

7. A needle clamp, for use in connection with the needle bar of a sewing machine, comprising in combination, a hollow body removably fastenable to said needle bar, a cylindrical member having a cylinder axis and being slidably movable axially of said axis in the interior of said body and having a surface inclined relative to said axis, a set screw in threaded engagement with said body and having a center line, and being movable, at "right angle to said axis, said set screw having a conical end surface formed about said center line and engaging said inclined surface of said cylindrical member and thereby being operable to move said cylindrical member in the direction of said axis, said cylindrical member having a surface perpendicular to the direction of movement of said set screw and parallel to the direction of needle sewing movement and operable to engage a needle.

8. In a needle clamp, as claimed in claim 7, the angle between the conical surface and the center line of said set screw being smaller than the angle between said inclined surface and the axis of said cylindrical member.

References Cited in the file of this patent UNITED STATES PATENTS 244,500 Tisdale July 19, 1881 464,013 Diehl Dec. 1, 1891 1,430,930 Berger Oct. 3, 1922 1,740,853 Guhl Dec. 24, 1929 1,896,047 Grieb Jan. 31, 1933 FOREIGN PATENTS 680,684 Germany Sept. 5, 1939 

